Evidence suggests that an important stimulus behind the rise of early civilizations was the development of settled agriculture, which unleashed a series of changes in the organization of human communities that culminated in the rise of large ancient empires.

The exact time and place that crops were first cultivated successfully is uncertain. Many prehistorians believe that farming may have emerged in dependently in several different areas of the world when small communities, driven by increasing population and a decline in available food resources, began to plant seeds in the ground in an effort to guarantee their survival. The first farmers, who may have lived as long as 10,000 years ago, undoubtedly used simple techniques and still relied primarily on other forms of food production, such as hunting, foraging, or pastoralism. The real breakthrough took place when farmers began to cultivate crops along the floodplains of river systems. The advantage was that crops grown in such areas were not as dependent on rainfall and therefore produced a more reliable harvest. An additional benefit was that the sediment carried by the river waters deposited nutrients in the soil, thus enabling the farmer to cultivate a single plot of ground for many years without moving to a new location. Thus, the first truly sedentary (that is, nonmigratory) societies were born. As time went on, such communities gradually learned how to direct the flow of water to enhance the productive capacity of the land, while the introduction of the iron plow eventually led to the cultivation of heavy soils not previously susceptible to agriculture.

The spread of this river valley agriculture in various parts of Asia and Africa was the decisive factor in the rise of the first civilizations. The increase in food production in these regions led to a significant growth in population, while efforts to control the flow of water to maximize the irrigation of cultivated areas and to protect the local inhabitants from hostile forces outside the community provoked the first steps toward cooperative activities on a large scale. The need to oversee the entire process brought about the emergence of an elite that was eventually transformed into a government.

The first clear steps in the rise of the first civilizations took place in the fourth and third millennia B.C. in Mesopotamia, northern Africa, India, and China. How the first governments took shape in these areas is not certain, but anthropologists studying the evolution of human communities in various parts of the world have discovered that one common stage in the process is the emergence of what are called “big men” within a single village or a collection of villages. By means of their military prowess, dominant personalities, or political talents, these people gradually emerge as the leaders of that community. In time, the “big men” become formal symbols of authority and pass on that authority to others within their own family. As the communities continue to grow in size and material wealth, the “big men” assume hereditary status, and their allies and family members are transformed into a hereditary monarchy.

The appearance of these sedentary societies had a major impact on the social organizations, religious beliefs, and way of life of the peoples living within their boundaries. With the increase in population and the development of centralized authority came the emergence of the cities. While some of these urban centers were identified with a particular economic function, such as proximity to gold or iron deposits or a strategic location on a major trade route, others served primarily as administrative centers or the site of temples for the official cult or other ritual observances. Within these cities, new forms of livelihood appeared to satisfy the growing need for social services and consumer goods. Some people became artisans or merchants, while others became warriors, scholars, or priests. In some cases, the physical division within the first cities reflected the strict hierarchical character of the society as a whole, with a royal palace surrounded by an imposing wall and separate from the remainder of the urban population. In other instances, such as the Indus River Valley, the cities lacked a royal precinct and the ostentatious palaces that marked their contemporaries elsewhere.

证据指出早期文明崛起的重要原因是定居农业的发展。农业的发展引发了人类社群组织结构的一系列变化并在古代帝国的崛起中发展到顶点。 虽然农作物首次成功培植的准确时间和地点还未确定，但是很多史前学家相信农业有可能是在世界不同地方独立发展起来的。因为人口增加，食物资源匮乏，一些小社群开始在土地上播下种子以确保它们的存活。最早的农民有可能生活在一万年前。可以确定的是他们使用简单的耕作技术，并且仍然主要依赖其他形式获得食物，比如说打猎、采集或放牧。当农民开始沿着河流的泛滥平原耕作的时候，农业史上才取得了真正的突破性进展。其优势在于，在这些地方种植的农作物不会那么依赖降水，因此收成更加有保障。另外一个优势在于，河水带来的沉积物给土壤增加了养料，因此农民可以很多年在同一块土地上耕作，从而不需要转移到新地方。这样一来，第一批真正意义上的农耕社会诞生了。再接下来，这些社群逐渐学会如何改变水的流向以提高土地的生产力，而铁犁的使用最终使农作物得以在原来不适宜耕种的粘重土壤上耕作。 这种河谷农业在亚洲和非洲各个地方的传播是最早文明崛起的关键因素。在这些地方食物产量增加导致人口显著增长。与此同时，社群努力控制水流，以便最大程度上确保耕作区的灌溉；社群还努力保护当地居民不受到社群外敌对力量的伤害。这些努力引发了社群内部更大规模的合作活动。对合作活动的监管产生了精英阶层，这些精英们最终转变成政府组织。 最早文明崛起中的第一步明显的发生在公元前4世纪和3世纪的美索不达米亚，北非，印度和中国。最早的政府在这些地方是如何形成的不得而知，但是研究世界各地人类社群发展演变的人类学家已经发现在政府形成过程中都存在一个共同的阶段，那就是在一个或几个村落中都出现了 “大个子”。“大个子”通过他们的军事力量，霸道的性格，或政治天赋，逐渐成为了那个群体的领导者。最终，“大个子”正式成为权威的象征并且能把权威传给他们家族的其他人。随着社群进一步发展繁荣，“大个子”就具有了世袭地位，他们的支持者和家庭成员也具有了世袭权利。 这些农耕社会的出现对社会组织、宗教信仰和社群内部的人们生活方式有重大的影响。因为人口增长和中央集权的发展，伴随而来的是城市的出现。某些城市中心具有特定的经济功能，比如说接近金矿或铁矿或处于主要贸易路线的战略地位。还有一些城市是主要是行政中心或是用来官方敬拜的寺庙或举行庆祝仪式的地方。在这些城市，新的谋生手段开始出现，以满足日益增长的对社会服务和消费品的需求：有些人成了工匠和商人，有些人成了战士，学者或牧师。在一些情况下，早期城市的地理区域划分反映了社会整体的严格等级制度，一堵威风凛凛的墙把皇宫和其余的城市居民隔开。然而，在另外一些地方，比如说印度河流域，城市则缺乏专门的皇家区和豪华的宫殿。